/*
 * Copyright 2012-2024 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * copy from org.springframework.boot.configurationprocessor.metadata.ConfigurationMetadata
 */

package org.noear.solon.configurationprocessor.metadata;

import java.util.*;

/**
 * Configuration meta-data.
 *
 * @author Stephane Nicoll
 * @author Phillip Webb
 * @see ItemMetadata
 * @since 1.2.0
 */
public class ConfigurationMetadata {

    private final Map<String, List<ItemMetadata>> items;

    private final Map<String, List<ItemHint>> hints;

    public ConfigurationMetadata() {
        this.items = new LinkedHashMap<>();
        this.hints = new LinkedHashMap<>();
    }

    public ConfigurationMetadata(ConfigurationMetadata metadata) {
        this.items = new LinkedHashMap<>(metadata.items);
        this.hints = new LinkedHashMap<>(metadata.hints);
    }

    public static String nestedPrefix(String prefix, String name) {
        String nestedPrefix = (prefix != null) ? prefix : "";
        nestedPrefix += nestedPrefix.isEmpty() ? name : "." + name;
        return nestedPrefix;
    }

    private static <T extends Comparable<T>> List<T> flattenValues(Map<?, List<T>> map) {
        List<T> content = new ArrayList<>();
        for (List<T> values : map.values()) {
            content.addAll(values);
        }
        Collections.sort(content);
        return content;
    }

    /**
     * Add item meta-data.
     *
     * @param itemMetadata the meta-data to add
     */
    public void add(ItemMetadata itemMetadata) {
        add(this.items, itemMetadata.getName(), itemMetadata, false);
    }

    /**
     * Add item meta-data if it's not already present.
     *
     * @param itemMetadata the meta-data to add
     * @since 2.4.0
     */
    public void addIfMissing(ItemMetadata itemMetadata) {
        add(this.items, itemMetadata.getName(), itemMetadata, true);
    }

    /**
     * Add item hint.
     *
     * @param itemHint the item hint to add
     */
    public void add(ItemHint itemHint) {
        add(this.hints, itemHint.getName(), itemHint, false);
    }

    /**
     * Merge the content from another {@link ConfigurationMetadata}.
     *
     * @param metadata the {@link ConfigurationMetadata} instance to merge
     */
    public void merge(ConfigurationMetadata metadata) {
        for (ItemMetadata additionalItem : metadata.getItems()) {
            mergeItemMetadata(additionalItem);
        }
        for (ItemHint itemHint : metadata.getHints()) {
            add(itemHint);
        }
    }

    /**
     * Return item meta-data.
     *
     * @return the items
     */
    public List<ItemMetadata> getItems() {
        return flattenValues(this.items);
    }

    /**
     * Return hint meta-data.
     *
     * @return the hints
     */
    public List<ItemHint> getHints() {
        return flattenValues(this.hints);
    }

    protected void mergeItemMetadata(ItemMetadata metadata) {
        ItemMetadata matching = findMatchingItemMetadata(metadata);
        if (matching != null) {
            if (metadata.getDescription() != null) {
                matching.setDescription(metadata.getDescription());
            }
            if (metadata.getDefaultValue() != null) {
                matching.setDefaultValue(metadata.getDefaultValue());
            }
            ItemDeprecation deprecation = metadata.getDeprecation();
            ItemDeprecation matchingDeprecation = matching.getDeprecation();
            if (deprecation != null) {
                if (matchingDeprecation == null) {
                    matching.setDeprecation(deprecation);
                } else {
                    if (deprecation.getReason() != null) {
                        matchingDeprecation.setReason(deprecation.getReason());
                    }
                    if (deprecation.getReplacement() != null) {
                        matchingDeprecation.setReplacement(deprecation.getReplacement());
                    }
                    if (deprecation.getLevel() != null) {
                        matchingDeprecation.setLevel(deprecation.getLevel());
                    }
                    if (deprecation.getSince() != null) {
                        matchingDeprecation.setSince(deprecation.getSince());
                    }
                }
            }
        } else {
            add(this.items, metadata.getName(), metadata, false);
        }
    }

    private <K, V> void add(Map<K, List<V>> map, K key, V value, boolean ifMissing) {
        List<V> values = map.computeIfAbsent(key, (k) -> new ArrayList<>());
        if (!ifMissing || values.isEmpty()) {
            values.add(value);
        }
    }

    private ItemMetadata findMatchingItemMetadata(ItemMetadata metadata) {
        List<ItemMetadata> candidates = this.items.get(metadata.getName());
        if (candidates == null || candidates.isEmpty()) {
            return null;
        }
        candidates = new ArrayList<>(candidates);
        candidates.removeIf((itemMetadata) -> !itemMetadata.hasSameType(metadata));
        if (candidates.size() > 1 && metadata.getType() != null) {
            candidates.removeIf((itemMetadata) -> !metadata.getType().equals(itemMetadata.getType()));
        }
        if (candidates.size() == 1) {
            return candidates.get(0);
        }
        for (ItemMetadata candidate : candidates) {
            if (nullSafeEquals(candidate.getSourceType(), metadata.getSourceType())) {
                return candidate;
            }
        }
        return null;
    }

    private boolean nullSafeEquals(Object o1, Object o2) {
        if (o1 == o2) {
            return true;
        }
        return o1 != null && o1.equals(o2);
    }

    @Override
    public String toString() {
        StringBuilder result = new StringBuilder();
        result.append(String.format("items: %n"));
        this.items.values().forEach((itemMetadata) -> result.append("\t").append(String.format("%s%n", itemMetadata)));
        return result.toString();
    }

}

